drop if (exporter=="SYR" | importer=="SYR")
drop if (exporter=="NIG" | importer=="NIG")
drop if (exporter=="JAM" | importer=="JAM")
drop if (exporter=="JPN" | importer=="JPN")
drop if (exporter=="BRA" | importer=="BRA")
drop if (exporter=="UK" | importer=="UK")
drop if (exporter=="THA" | importer=="THA")
drop if (exporter=="DEN" | importer=="DEN")
drop if (exporter=="DRP" | importer=="DRP")
drop if (exporter=="CHI" | importer=="CHI")
drop if (exporter=="IRQ" | importer=="IRQ")
drop if (exporter=="SKO" | importer=="SKO")
drop if (exporter=="NOR" | importer=="NOR")
drop if (exporter=="ARG" | importer=="ARG")
drop if (exporter=="GRE" | importer=="GRE")
drop if (exporter=="MAL" | importer=="MAL")
drop if (exporter=="HON" | importer=="HON")
drop if (exporter=="EGT" | importer=="EGT")
drop if (exporter=="HAI" | importer=="HAI")
drop if (exporter=="CAN" | importer=="CAN")
drop if (exporter=="SEN" | importer=="SEN")
drop if (exporter=="ALG" | importer=="ALG")
